Various aspects of the present invention relate generally to mechanical locks, and specifically to cylindrical locks requiring a physical key to open.
A mechanical lock is a fastening device that releases when a certain condition is met. For example, a pin-tumbler lock includes pins with a gap in each of the pins at different levels and springs to radially push the pins such that the gaps are not aligned at an interface between an outer cylinder and an inner cylinder. When the proper key is inserted into a keyhole of the lock, the pins are raised to allow the individual gaps in the pins to be at the same level as the interface, which allows the inner cylinder of the lock to rotate, opening the lock.
A wafer-tumbler lock is similar to the pin-tumbler lock. However, the wafers include large gaps within the keyhole and springs that radially push the wafers such the bottom of the wafer extends into an outer cylinder from an inner cylinder. When the proper key is inserted into the keyhole, the key fits within the gaps and raises the wafers individually, which aligns the top and bottom of the wafer with the inner cylinder's edge and allows the inner cylinder to rotate within the outer cylinder, opening the lock.
A disc-tumbler lock utilizes a sidebar to prevent the lock from opening, and slotted retaining discs are used to determine the position of the sidebar. When the proper key is inserted into the keyhole, the key rotates the discs (similar to the tumblers of a safe) to align the slots of the discs, which allows the sidebar to drop into the slots, opening the lock. Unlike the pin-tumbler lock and the wafer-tumbler lock, the disc-tumbler lock does not include springs.
A tubular lock includes a set of pins similar to the pin-tumbler lock, except that the pins of the tubular lock are aligned parallel to the axis of the lock, as opposed to radially as in the pin-tumbler lock. When the proper key is inserted into the keyway, indentations on the tip of the key push the pins axially (not radially as with the pin-tumbler lock) to align with edges of a cylinder allowing the cylinder to rotate.
A key is a device used to operate a lock and typically includes a head (also referred to as the bow) and a shaft (also referred to as a blade). The shaft usually includes a set of levels and/or bumps that are coded to a specific lock as described above. The head allows a user grip the key to apply torque to rotate the inner cylinder of a lock within the outer cylinder when the proper key is inserted to the keyhole (also referred to as the keyway) of the lock.